The present invention relates generally to a three-way temperature responsive regulator valve, and more particularly to such a valve in which a wax-type temperature responsive device is utilized to displace a valve poppet for controlling the flow of fluid through selected ports in the valve body.
Thermostatically controlled three-way valves are frequently employed for regulating the flow of fluid through various circuits in fluid utilizing systems on which the fluid is subjected to temperature fluctuations. The fluid utilizing systems include those which use any fluids such as hydraulic fluids, lubricating oils, and coolant fluids for system control and/or operational purposes such as employed in internal combustion engines.
Three-way temperature regulator valves, as conventionally known and used, usually contain a thermostatic control in or near one of the three fluid conveying ports or passageways in the valve body in order to operate a valve member such as a valve poppet in response to temperature variations in the fluid for the purpose of dividing or mixing the fluid within the valve. The thermostatic control frequently employed in three-way valves is a wax-type thermally responsive actuator in which a body of wax or a wax-type material is contained in a housing provided with a diaphragm-like end wall which engages and moves a valve-poppet displacing piston in response to thermally induced volume changes in the body of wax.
While the wax-type thermally responsive actuators provide a high level control over the operation of the valve in response to fluid temperature variations, it has been found that this type of actuator periodically dysfunctions, causing the valve to fail or operate in an impaired manner. Primarily, this problem with the wax-type actuators is due to the loss of wax by leakage of the wax from the wax-containing housing.
In order to assure that a three-way valve containing a wax-type thermally responsive actuator can be operated in the event of any emergency such as a dysfunction of the wax-type actuator, a manual override arrangement such as described in U.S. Pat. No. 2,810,523 has been provided. Such a manually operated arrangement includes a crank fixedly attached to a threaded valve stem so that the flow-controlling valve member or valve poppet can be manually positioned within the valve body to provide the desired control over the flow of fluid through the valve.
Previously known three-way valves using wax-type thermally responsive actuators including those with manual overrides, such as described in the aforementioned patent, suffer several shortcomings or drawbacks which detract from their overall usefulness and acceptability. For example, when a wax-type actuator becomes inoperative it is commonly replaced with a new actuator. This replacement has heretofore been a relatively complex and time consuming task, often requiring substantial disassembly of the valve so as to result in a considerable downtime of the valve or, in some instances, the removal of the valve from the fluid system. A valve typically requiring extensive effort and valve downtime for the replacement of a defective wax-type actuator is the type described in the aforementioned patent where the wax-type actuator is an integral component of the valve mechanism in the valve body
Another drawback to the previously known three-way valves containing the wax-type thermal actuators is due to the manual override mechanism which often requires the use of a special crank arrangement fixedly attached to the valve or the use of special tooling for manually operating the valve.